Conventional storage arrays are often implemented with two controllers. One controller is for redundancy. The disk drive enclosures are directly connected to the controllers. Such an implementation poses a limit on the number of drives that can be accessed by a given storage array. In addition, only one controller can be used for redundancy and load sharing for the input/output (I/O) to the storage array.
It would be desirable to implement a clustered array controller for global redundancy in a Storage Area Network (SAN) that extends the level of controller redundancy and/or load sharing.